Phosphonium salts and derivatives and their preparation



United States Patent 3,332,962 PHOSPHONIUM SALTS AND DERIVATIVES AND THEN PREPARATION Martin Grayson, Norwalk, Patricia Tarpey Keough, Ridgefield, and Michael M. Rauhut, Norwalk, Conn., assignors to American Cyanamid Company, Stamford, Conn., a corporation of Maine No Drawing. Filed June 4, 1963, Ser. No. 285,224 8 Claims. (Cl. 260-3323) The present invention relates to organophosphorus compounds and to a method of preparing same. More particularly, the instant discovery concerns phosphonium salt derivatives of tertiary phosphines.

It has been found that tertiary phosphines generally will react with halo-substituted ethanol to produce the corresponding trialkyl-, tricycloalkyl-, or tri-aryl-Z-hydroxyethylphosphonium salts. In turn, these salts may be acylated using a lower alkanoic anhydride, lower alkanoic acid, or the like, to produce their corresponding tri-alky1-, tricycloalkyl-, or triaryl-2-acetoxyethylphosphonium salts.

The following equations illustrate this general reaction:

R1R2R3P XOHzCHzOH R R R P CHzCIEOH'X (B) n mn ri omomon-x esterifying agent R R R P CHzCHaOY'X R R R each representing, as will be seen hereinafter, alkyl, cycloalkyl and aryl, X representing halogen or tetraphenyl borate, and Y representing the residue of an acylating or esterifying agent. The following is a typical embodiinent of generic Equations A and B, above;

More specifically, in generic Equations A, B and C, above R R and R each represent alkyl C C1e substituted alkyl C -C cycloalkyl, :and aryl; X represents halogen, such as bromo, chloro and iodo, and tetraphenyl borate; and Y in Equations B and C represents the residue of an acylating agent as shown in the specific embodiments, supra.

Typical tertiary phosphine reactants are the following:

trimethylphosphine, triethylphosphine, tripropylphosphine, tributylphosphine, tripentylphosphine', trihexylphosphine, triheptylphospine, trioctylphosphine, trinonylphosphine, tridecylphosphine,

triundecylphosphine,

trido de cylphosphine, tritridecylpho s phine, tritetradecylphosphine, tripentadecylphosphine, trihexadecylphosphine,

dode cyldiethylphosphine, dioctylpropylphosphine, diethylbutylphosphine, butylethylhexylphosphine tri Z-methoxypentyl phosphine, tris-2-cyanoethylphosphine, diethyl-Z-ethoxyheptylphosphine, tricyclopropylphosphine, tricyclohexylphosphine, triphenylphosphine,

diphenyln aphthylphosphine, trixylylphosphine,

tritolylpho sphine, tris( para-ethoxyphenyl phosphine, tris (p arachlorophenyl) phospine, tris (2-chlorophenyl phosphine, tris( 3-bromophenyl) phosphine, and the like.

Typical esterifying agents follow: lower alkanoic anhydrides, such as acetic anhydride, propionic anhydride, butanoic anhydride; lower alkanoic acids, such as formic acid, acetic acid, propionic acid, butanoic acid; acylating (C -C alkanoyl) halides, such as acetyl chloride, propionyl bromide, butyryl iodide, octanoyl chloride, dodec: anoyl bromide, stearyl chloride, hexanoyl bromide; isopropenyl acetate; aryl sulfonyl halides, such as para-toluenesulfonyl chloride, phenyl sulfonyl bromide, 2,4-dimethyl-' phenylsulfonyl chloride; alkyl (lower) chloroformates, such as ethylchloroformate, butylchloroformate; alkyl (lower) carbonates, such as diethylcarbonate, dipropylcarbonate, dibutylcarbonate; ketene; dimethyl sulfate; nitrosyl chloride; and trimethyl phosphate.

In Equation C, above, typical suitable inorganic and organic bases are: alkali metal hydroxides, such as sodium hydroxide, potassium hydroxide, lithium hydroxide; alkali metal carbonates, such as sodium carbonate, potassium carbonate, lithium carbonate; alkaline earth metal hydroxides, such as magnesium hydroxide, barium hydroxide, calcium hydroxide; alkaline earth metal carbonates, such as magnesium carbonate, barium carbonate, calcium carbonate; activated alumina; and quaternary ammonium hydroxides, such as tetraalkyl (lower) ammonium hydroxides, including tetramethylammonium hydroxide, tetrapropyl-ammonium hydroxide, and tetrabenzylamrnonium hydroxide; and basic ion exchange resins.

The reaction in Equation A hereinabove is carried out at a temperature in the range of 30 C. to 250 C., preferably 60 C. to 180 C. The Equation B reaction, above; is best carried out at a temperature in the range of 5 C. j to C. As to Equation C, above, this reaction is gencess of about 10% by weight of the acylating agent relative to the phosphoniurn salt reactant is preferred. Generally in Equations A and C stoichiometric amounts of the reactants are employed.

-'.l.ypical are: polymeric quaternary ammonium salts, efgz, polymeric trimethylbenzyl ammonium chloride, etc, p

The reactions of Equation A, above, are best carried out in the presence of an inert organic solvent, i.e., a solvent which does not enter into or otherwise interfere with the reaction under the conditions contemplated herein. Typical solvents are dimethoxyethane, dioxane, ethylacetate, tetrahydrofuran, and the like.

The reactiops of Equation B similarly are best carried out in the presence of an inert organic solvent of the type described for Equation A, as well as acetic acid, dimethylformamide, diglyme, and the like.

As to Equation C, typical suitable inert organic solvents in which the phosphonium salt is solvent, which solvents do not interfere or enter into reaction to any substantial degree, are dimethoxyethane, dioxane, dimethylforrnamide, diglyme, acetonitrile, ethylacetate, tetrahydrofuran, and other like linear and cyclic ethers, acetate esters (lower alkyl).

Alternatively, it has been found pursuant to the instant discovery that the products of Equation A, above, may be converted directly to the products of Equation C, thusly,

in the presence of any base given above for Equation C and at a temperature in the range of 100 C. to 250 C. As in Equation C, a solvent of the type given hereinabove for Equation C is suitable and herein contemplated. If desired, the reaction may be carried out in the presence of a dehydrating agent, such as a siliceous agent including silica (e.g. silica gel), silica-alumina, and the like, in which other inert organic solvents are also suitable, e.g. aromatic hydrocarbons, such as toluene, benzene, xylene, cyrnene, and the like, methylene chloride, ethylene chloride, etc.

The products of Equations A, B, C and D above are useful as fire retardants in plastics, e.g., from 0.5 to 30 parts by weight of any one of above compounds when incorporated into 100 parts by weight of a thermoplastic polymer material, such as polyethylene, polypropylene, polystyrene, polyacrylate, polymethylmethacrylate, or the like, provides enhances fire retardance to the polymer material upon exposure to an open flame.

While the following examples specify certain details as to certain embodiments of the present invention, it is not intended that these details impose unnecessary limitations upon the scope of the instant discovery, excepting of course that these limitations appear in the appended claims:

Example I.TributyZ-Z-hydroxyethylphosphonium tetraphenylborate Tributyl 2 hydroxyethylphosphonium bromide, obtained from combining tributylphosphine and 2-bromoethanol in 1,2-dimethoxyethane and refluxing under nitrogen, is dissolved in water and treated with excess 0.1 N sodium tetraphenylboron. The resulting precipitate is filtered and recrystallized from ethanol to yield product tributyl-Z-hydroxyethylphosphonium tetraphenylborate with melting point 124 C.-125 C. Analysis of product (Found: C, 80.03; H, 9.00; P, 5.35. C H O requires: C, 80.55; H, 9.25; IP, 5.47%).

As is evident from this example, the halide salts of Equation A may be converted, in situ or after recovery thereof, to the corresponding tetraphenylborate salts.

Example II.-TriburyI-Z-acetoxyethylphosplzonium bromide 1,2-dimethoxyethane (275 milliliters), freshly distilled from calcium hydride, 2-bromoethanol (133 grams, 1.06 moles), and tributylphosphine (204 grams, 1.01 moles) are combined under nitrogen and refluxed at 85 C. overnight with stirring. A heavy oil forms Within an hour. Isopropenyl acetate (320 grams, 3.2 moles) and 48% HBr (3 drops) are slowly added to the reaction mixture which is then refluxed 18 hours. Volatile components are removed in vacuo at 70 C. Product (372.5 grams; 99.9% yield) remains as a thick hygroscopic oil, which could be forced to crystallize by stirring in a benzene-petroleum ether (boiling point 30 C.-60 C.) mixture. Crystalline tributyl-2-acetoxyethylphosphonium salt is obtained from part of the oily product by freeze drying a benzene solution of the oil.

Example III.Tributyl-2-acetoxyethylplzosplzonium tetraphenylborate Tributyl-2-acetoxyethylphosphonium bromide oil (16.2 grams produced as in Example II, above) is dissolved in water and treated with sodium tetraphenylboron (15 grams) dissolved in water. A white precipitate appears which is filtered and recrystallized from ethanol containing enough acetonitrile to cause solution at the boiling point of the mixture. Tributyl-2-acetoxyethylphosphonium tetraphenylborate (16.7 grams) is obtained with melting point of 177 C.-179 C. Analysis of product (Found: C, 76.65; H, 8.83; P, 5.24. C H O BP requires: C, 78.93; H, 8.94; P, 5.10%). 0

Example I V.Triphenyl-Z-acetoxyethylphosph0nium iodide 2-iodoethyl acetate is prepared from the nucleophilic exchange reaction of sodium iodide and Z-chloroethylacetate in refluxing acetone under nitrogen (boiling point 86 C.-90 C. at 33 milliliters mercury). Triphenylphosphine (7.35 grams) is reacted with 2-iodoethylacetate) 24 grams) under nitrogen with stirring at 80 C. for 4.5 hours. The excess 2-iodoethylacetate is distilled off in vacuo. Crude, brown crystalline product (14.20 grams) is obtained by Washing oily residue with ether. It is washed with ether, ethylacetate, and acetone and recrystallized from acetonitrile to give product (7.90 grams) with melting point 161 C.-163 C. Analysis of product (Found: C, 55.16; H, 4.80; I, 26.77; P, 6.45. C H O IP requires: C, 55.47; H, 4.66; I, 26.66; P, 6.51%.)

Example IV represents still another embodiment of the present invention wherein the product salts of Equation B, above, are prepared directly from the reaction of a 2- haloethyl acetate with a tertiary phosphine of the type contemplated herein.

The process of Example IV, above, maybe carried out using any of the tertiary phosphine reactants contemplated herein and the corresponding tri-substituted-Lacetoxyethylphosphonium halide produced and recovered, according to the following equation It e RIRZRKP +xomornoo-om RIRZR3PCHZCHZOYQGC wherein R R R X and Y have the meanings given hereinabove in Equations A and B.

Equation E is best carried out at a temperature in the range of 5 C. to C., preferably at the reflux temperature of the solvent employed. Typical inert organic solvents contemplated for Equation E are acetone, lower alkanol (ethanol, butanol), plus the solvents listed hereinabove for Equation C. The reaction under Equation E, as shown in Example IV, supra, is best carried out under inert conditions, such as under nitrogen. Other 2-haloethyl acetate reactants contemplated herein are 2-bromoethyl acetate and 2-chloroethyl acetate.

Tables A, B, C, D and E, which follow, correspond to Equations A, B, C, D and E, respectively. The examples in Table A and B are carried out essentially as in Examples I and II, respectively supra, excepting of course as shown in Tables A and B. The examples in Table C are carried out essentially as in Example LX, infra, excepting of course as shown in Table C. Likewise, the products of Table D are recovered essentially as in Example LX, infra. The examples in Table E are carried out essentially as in Example IV, supra, excepting of course as shown in Table E.

TABLE B.Contlnued Example Product of 6-) Moles 6 A Moles Solvent Milliliters Temp., Product No. ExleImple RQPCHiCHLOH X A XXVIL XI 1. p-Toluenesulfonyl 1. 0 DME, 200 ml 60 2-(p-toluenesulfonyl oxy) ethyltrichloride. dodecylphosphomum chloride.

XXVIII XIII 1. 0 Trimethyl Phos- 1. 1 Acetic acid, 500 80 Z-dimethylphosphatoethyltriethyl phate. ml. phosphomum chloride.

XXIX. XII 1. 0 Propionic Acid 2. 4 DMF 1 300 ml... 2-propi0ny10xycthyltrihexedecylphosphonimn chloride.

XXX XIV 1. 0 Butanoic An- 1. O DMF, 1,000 2-butyryloxyethylbutylethylhexylh dride. phosphonium chloride XXXL XV 0.8 Acetic Acid 4. 0 None 118 2-acetoxyethyldiethykzethoxyethylphosphonium chloride.

XXXIL-.. XVI 0.9 Acetyl Chloride 1. O DME 200 ml 65 Z-acetoxyethyltricyclohexylphosphonium bromide.

XXXIII XVII 1. 0 Hexanoyl Chloride 1. 9 Dioxane, 150 ml- 25 Z-hexanoyloxyethyltrlcyclopentyb phosphonimn chloride.

XXXIV XIX 1. 0 Acetic Anhydride. G. 0 None 100 2-acetoxyethyltriphenyl phosphonium iodide.

XXXV XVIII 1. 1 Stearyl Chloride- 3. 3 DME, 700 ml 2-stcaryloxyethyldiphenylnaphthylphosphonimn iodide.

XXXVL XX 1. 0 Dodecenoyl Bro- 4. 0 DMF, 1,000 ml. 40 2-dodecanoyloxyethyltri-(parachloromide. phenybphosphonium chloride.

XXXVII. XXI 1. 0 Phenylsulfonyl 1. 0 Dioxane, 600 m.l 2-(phenylsulionylcxy)-ethyltri(para Bromide. tolyl)phosphoniun1 chloride.

XXXVIII. V 1. 0 Et-hylchloroformate. 2.0 Diglyme, 300 ml... 40 Z-(ethoxycerbonyloxy) -ethyltrln1ethyl phosphonium bromide.

XXXIX VII 0. 9 Dipropyl carbonete 3. O DME, 250 ml 100 2-(propoxycarbonyloxy)-ethy1tributylphosphonium chloride.

XL VII 1. 0 Ketene 1. 0 THF, 500 ml Z-acetoxyethyltributyl phosphonium chloride.

1 DMF=dimethylformamide.

TABLE C 65 9 G9 9 R R R POH2CH2OY'X Base R R R PcH -OHn'X Example Product of Moles of Solvent 1 Temp.,

No. Example R R R PCHQCHIO Y'X Base Base Milliliters 0. Product No. (ml.)

XLI XXII 1. 0 K2 CO3 1. U DME, 300 ml 83 vllljlyltriglethylphosphonium IOlDl e. XLII XXIII 1. 0 Na. CO3 2.0 Dioxenc, 300 ml--. 100 virfiltrfimtylphosphonium c 1 or e. XLIII XXIV 1.0 Li: CO3 4.0 Etslagl alcetate, Do.

m XLIV XXV 2. 0 Mg(COa) 8.0 Diglyme Vingliaributylphosphonium 1o 1 e. XLV XXVI 0.5 Ba(OH)g 1. 0 Acetonitrile, 500 80 Vilgltrjsobutylphosphonium c on e. XLVI XXV II 0. 9 Ca(0H)g 1. 1 THF, 600 m1 60 vliigltlilgodecylphosphonium c or e.

XLVII XXVIII 1. 0 Polymeric trl- 4. 0 DME, 400 ml.- 85 Vinyltriethylphosphonlum methylbenzyl chloride. ammonium chloride XXIX 1. 0 KOH 1. 0 THF vinyltrihexedecylphosphonium chloride.

XXX 1. 0 N aOH 1. 0 Acetonitrile 20 Vinylbutylethylhexylphqsphonium chloride.

XXXI 1. 0 1.1011 1. 0 -.do 60 Vinyldiethyl-2-ethoxyethylphosphonium chloride.

LI XXXII 1. 0 Mg(OH): 3.0 THF 72 Vinyltricyclohexyl hosphonium broml e.

LII XXXIII 2.0 Ca(CO 1. 0 Dioxane Vinyltricyclopentyiphosphonium chloride.

LIII XXXIV 0. 5 BMCOa) 1- 0 DM 81 Vinglfjrlphenylphosphonium LIV XXXV 3.0 Polymeric trl- 1. 0 Dioxane- 97 Vinylphenylnaphthylphosethylberizyl phonium iodide. ammonlum hydroxide.

LV XXXVI 1. 0 d0 5. 0 DME 50 Vinyltrl(para-chlorophenyl) phosphonium chloride.

LVI XXXVII 1. 0 Activated 1. 0 THF 35 Vinyltri(para-tolyDphosumil flphonium chloride.

LVII XXXVIII 1. 0 Tctramethyl- 1. 7 Diglyme 42 Vinyltrlmethylphosphonium ammonium bromide. hydroxide.

LVIII XXXIX 2- 0 T trapropyl- 1. 0 DMF 37 Vinyltrlbutylphosphonium ammomum chloride. hydroxide.

LIX XL 1. 0 Tetrabenz y1- 1. 0 DME 25 D ammonium hydroxide.

1 When not specified the amount of solvent employed is 500 milliliters.

TABLE D ea 6 base 89 6 RIR3RSPOHQOH2OH'X R R R PCH=OHrX Example Product of Temp. 500Mi11iliters No. ExlaImple Base C. Dehydrating Agent of Solvent Product 120 Silica gel DME Vinyltrlbutylphosphonium chloride. 100 Silica-alumina. DME Vinyltridodecylphosphonium chloride. 220 THE Vinyltrihexadecylphosphonium chloride. 180 Silica-alumina Dioxane Vingldleithyl-2-eth0xyethyl-phosphonium G OI! 6. 150 Silica gel DME Vinyltiioyclohexylghosphonlurn bromide. 250 Dioxane vlinylligiphenylnap thy phosphonlum o e. 205 Dimmne Vinyltriphenylphosphonium iodide. 200 DME Vinyltrl(para-chlorophenyl)-phsphonlumchloride. 9 XXI Activated alumina. 175 DME Vlnyltri(para-tolyDphosphonium chloride.

l Finely-divided particulates.

TABLEE 0 Temp., Ex. No. Q} C. Solvent Product R R R P+XCH1CHiO CH;1

10 Tridodecylphosphlne X=Br Reflux Ethanol T1gdoId SyIQ-acetoxy-ethylphosphonium r0 e. 11 Tricyclohexylphosphine X=I 85 Acetonltrile Trlcgohexyl-Z-acetoxyethylphosphonium 10 e. 12 Trls(2-chlorophenyl)-phosphine X=Cl Reflux Acetone Tris(Zchlorophenyl)-2-aeet0xyethylphosphonium chloride. 13 Trls(Z-methoxypentylyphosphine;; X=I 50 Dioxane 2-acetoxyethylphosphoniumiodide;

By finely-divided particulates in Table D is intended 28 to 200 mesh. Larger or smaller particulates are likewise within the purview of the instant discovery.

Example LX.Tributylvinylphosphonium bromide ethyl acetate yields product tributylvinylphosphonium bromide (3.3 grams, 10.7 millimoles, yield with melting point 148 C.-150 C.) Further recrystallization from ethylacetate-acetonitrile raises the melting point to 151.5 C. to 152.5 C.

The products of Equations and Tables B, C, D and E hereinabove may be reacted, pursuant to the present in- Y vention and according to the reaction conditions of Equation C, supra, with a polyhydric alcohol of the formula HO(R)0H wherein R represents: alkylene C C cycloalkylene; ROR" wherein R and R" each represent lower alkyl url L 8 wherein R' and R each represent loweralkyl and the residue of glucose, pentaerythritol, insitol, sorbitol, and

mannitol. The product salt has the formula wherein R} R2 R3, and R and X have the meanings given hereinbefore.

The following examples illustrate this. reaction, Ex-

amples LXII through LXXIV being carried out essentially as in Example LXI, excepting as shown in Table F:

Example (C H PCH CH OCH CH OCHQCHZP (C H 13969231 Tributylvinylphosphonium bromide (30.8 grams, 0.10

mole) is mixed with 3.1 grams (0.05 mole) of ethylene glycol and five drops of 10% aqueous sodium hydroxide, and heated at C.l30 C. for 8 hours. The resulting clear syrup represents a quantitative yield of 2,2- (ethylenedioxy)diethyl-bis(tributylphosphonium bromide). Treatment of this syrup with a one normalsolution of sodium tetraphenyl boron yields a crystalline derivative, melting point C.156 C.

Analysis calculated for CqgHmgPgBgOzi C, 80.81; H, 9.22; P, 5.54. Found: C, 80.83; H, 9.26; P, 5.06.

As is evident from Table F, above, trialky1(lower) amines are likewise useful as bases in these reactions, e.g., triethylamine and tributylamine, and the like. When using these amines from about 1.0 to about 5.0 percent by weight thereof, based upon the total weight of reactants (1) and (2), is generally employed.

The products of Examples LXI through LXXIV may be employed as fire retardants in the manner defined hereinabove for the phosphonium salts of Equations B through E.

In Table F 500 milliliters of solvent is used in the examples. As illustrated in Example LXI, hereinabove, an excess of the alcohol reactant may be used as the solvent if desired.

Clearly, the instant discovery encompasses numerous modifications within the skill of the art. Consequently, while the present invention has been described in detail with respect to specific embodiments thereof, it is not intended that these details be construed as limitations upon the scope of the invention, except insofar as they appear in the appended claims.

We claim:

1. A compound of the formula [(R R R P-CH CH O R] X wherein R R and R each represent a member selected from the group consisting of alkyl C C alkoxy-substituted alkyl C C cyclopropyl, cyclopentyl and cyclohexyl, R represents a member selected from the group consisting of alkylene c -c cyclohexylene, R'OR wherein R and R" each represent lower alkyl,

LRIV 8 wherein R" and R each represent lower alkyl, and X is halogen.

2. The compound 3. The compound c 11 3PCH2CH2OCH2OCI-I2OCH2CH2P (C12H25 a 1 59692019 4. The compound 5. The compound 6. The compound 7. A method which comprises bringing into reactive contact a phosphonium salt selected from the group consisting of and an alcohol of the formula HO(R)OH in the presence of a base, and recovering the corresponding salt of the formula l on in which R and R each represent lower alkylene. and R further represents the residue of a member selected from the group consisting of glucose, pentaerythritol, inositol, sorbitol, and mannitol. 8. The process of claim 7 in which reaction is made to take place in an inert organic solvent.

omonio GHFLUCHQO omomr C 9 References Cited UNITED STATES PATENTS 4/1959 Dornfeld 260606.5

WALTER A. MODANCE, Primary Examiner.

JAMES A. PATTEN, Assistant Examiner. 

1. A COMPOUND OF THE FORMULA 